The snap-in groove of a wheel rim is a part acted upon by very heavy forces so that, on bending out the outer cylindrical part of the blank to make the outer wall of the snap-in groove, special care is necessary to see that there is the least possible loss in strength of the material. This danger of a loss in strength is likely on using spinning rollers because a spinning operation is frequently responsible for material flow. Furthermore, it has been normal in the industry for a groove to be produced by using two spinning rollers, one acting on the outside of the work and the other on its inside, the shortcoming here being that the outer spinning roller, against which the work is forced by the inner spinning roller, gives way elastically somewhat so that tight size limits may not be kept to and, in fact, the work has to be trued up in a later, further working step.